Reverse flow combustors for gas turbine engines typically include large and small exit ducts which are configured to reverse the flow of the hot combustion gases, between an upstream end of the combustor where the fuel nozzles are located to the downstream end of the combustor which is in fluid flow communication with the downstream turbine(s). In a reverse flow combustor, the small exit duct is often most susceptible to wear and/or lifecycle issues because its geometry and location in the combustor requires it to have a tight radius bend with more limited surface area available for air cooling and the like. Current designs of small exit ducts typically use ductile sheet metal to form the small exit duct, in order to overcome manufacturing challenges associated with the tight radius design. However, ductile materials are normally less durable than other components used in gas turbine engines, such as machined components and like.
Additionally, because most small exit ducts are either integrally formed with the liners of the reverse flow combustors or welded in place thereto, in the event that a small exit duct needs replacement it may become necessary to scrap the entire combustor or at least large portions thereof.
Improvements in reverse flow combustors are therefore sought.